When unconscious, victims appear to act normally based on muscle memory and can produce responses for basic questions. They cannot control their actions in any way during this time. When in this state, victims will appear emotionless and have slowed reaction times. Persons affected are also very passive and compliant with personnel.

This feels a little awkward to me (I think it's two sentences starting with "when" clauses) and also a little choppy. "Normally based on muscle memory" seems a little contradictory with "slowed reaction times," too. And they're not actually unconscious. Maybe try it like this:

When subject to SCP-XXXX's effect, victims appear to move normally based on muscle memory, albeit with slowed reaction times. They are very passive and compliant with personnel, willing to answer basic questions and follow commands, though they display a lack of affect. While they appear conscious, victims cannot control their actions in any way during this time.

most express dread in realization of the permanence of their situation

I think "on realizing" is better than "in realization of" here.

There was a single incident in Northern Canada where SCP-XXXX appeared on live local television that resulted in over 4,000 people's relocation to Site-116.

Just to tighten it up: "A single incident in Northern Canada, where SCP-XXXX-A appeared on live local television, resulted in over 4,000 people's relocation to Site-116."

SCP-XXXX-A is believed to possess memetic properties that are enhanced based on those effected.

"Affected." And I think it should be "the number of people it affects" or something like that.

Cases of SCP-XXXX-A manifesting and the number of living victims appear to grow at the same rate.

This isn't quite clear to me. "Manifestations of SCP-XXXX-A appear to become more frequent as the number of living victims increases."

After the implementation of Addendum-XXJ9

The policy is in the addendum, but it should probably be called Protocol XXJ9 or something like that.

Those who have been resettled on Site-116 have display an affinity to SCP-XXXX-A.

"Displayed," and I also think it should be "at" instead of "on."

Art, literature, and effigies of SCP-XXXX-A are common to find in the cells of subjects. These have been observed to be horded into a corner of the room.

"Hoarded." I think this could be one sentence. "Art, literature, and effigies of SCP-XXXX-A can commonly be found hoarded in the corners of subjects' rooms."

Anything created that has to do with SCP-XXXX-A are to be removed and incinerated. Any seen emulating SCP-XXXX-A is subject for termination.

"Any such items are to be removed and incinerated and their creators terminated, along with any subjects seen emulating SCP-XXXX-A."

If you wan't to help us

Rogue apostrophe.

In the corner of my eye, its just… Staring

Apostrophe goes in "it's" instead.

Medical teams are called in, and it was determined to be a normal return to previous cognitive state.

I get why you've shifted tense here, but it feels odd.

I think the added interviews are a big help. I like that the sloth isn't even visible to them all the time, but they know it's always lurking somewhere.